Apparatus and method for forming inflated containers

ABSTRACT

An apparatus for forming inflated containers generally includes a mechanism that conveys a web of film along a path of travel, the film web including one or more pre-formed flexible containers; an inflation assembly positioned adjacent the travel path to direct gas into the containers, thereby forming inflated containers; and a device for sealing closed each inflated container. Various means for improving the reliability and consistency of inflation of the containers are also disclosed.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to inflated containers and, moreparticularly, to a simplified and improved apparatus and process forproducing gas-inflated cushions for packaging.

[0002] Various apparatus and methods for forming inflated cushions orpillows are known. Such inflated containers are used to package items,by wrapping the items in the cushions and placing the wrapped items in ashipping carton. The cushions protect the packaged item by absorbingimpacts that may otherwise be fully transmitted to the packaged itemduring transit.

[0003] Conventional apparatus for forming inflated cushions tend to berather large and complex machines, which are expensive and cumbersome tomaintain. Further, conventional apparatus often do not reliably inflatethe cushions, with some being under-inflated or not inflated at all.

[0004] Accordingly, there is a need in the art for a simpler and lessexpensive apparatus for producing gas-filed packaging cushions, andwhich more reliably and consistently inflates such cushions.

SUMMARY OF THE INVENTION

[0005] Those needs are met by the present invention, which, in oneaspect, provides an apparatus for forming inflated containers,comprising:

[0006] a. a mechanism that conveys a web of film along a path of travel,the film web comprising a film having a pair of longitudinal side edgesand a longitudinal fold to form a longitudinally-folded film web havingtwo juxtaposed film plies with the side edges being positioned adjacentto one another, the folded film web defining

[0007] 1) a closed longitudinal edge formed by the longitudinal fold,

[0008] 2) an open longitudinal edge positioned opposite andsubstantially parallel to the closed longitudinal edge, the openlongitudinal edge formed from the adjacently-positioned longitudinalside edges, and

[0009] 3) one or more pre-formed flexible containers, each of thecontainers being capable of holding therein a quantity of gas and having

[0010] (a) an open edge for receiving such gas, the open edge beingformed by the open longitudinal edge, and

[0011] (b) an opposing closed edge formed by the closed longitudinaledge;

[0012] b. an inflation assembly positioned adjacent the travel path andcapable of

[0013] 1) urging the open longitudinal edge towards the closedlongitudinal edge such that a crease forms at the closed edge of each ofthe pre-formed containers, thereby forming creased, pre-formedcontainers, and

[0014] 2) directing a stream of gas into the open edge of each creased,pre-formed container, thereby forming inflated containers; and

[0015] c. a device for sealing closed the open edge of each inflatedcontainer.

[0016] Another aspect of the invention provides method for forminggas-filled cushions, comprising:

[0017] a. conveying a web of film along a path of travel, the film webcomprising a film having a pair of longitudinal side edges and alongitudinal fold to form a longitudinally-folded film web having twojuxtaposed film plies with said side edges being positioned adjacent toone another, the folded film web defining

[0018] 1) a closed longitudinal edge formed by the longitudinal fold,

[0019] 2) an open longitudinal edge positioned opposite andsubstantially parallel to the closed longitudinal edge, the openlongitudinal edge formed from the adjacently-positioned longitudinalside edges, and

[0020] 3) one or more pre-formed flexible containers, each of thecontainers being capable of holding therein a quantity of gas and having

[0021] (a) an open edge for receiving such gas, the open edge beingformed by the open longitudinal edge, and

[0022] (b) an opposing closed edge formed by the closed longitudinaledge;

[0023] b. urging the open longitudinal edge towards the closedlongitudinal edge such that a crease forms at the closed edge of each ofthe pre-formed containers, thereby forming creased, pre-formedcontainers;

[0024] c. directing a stream of gas into the open edge of each creased,pre-formed container, thereby forming inflated containers; and

[0025] d. sealing closed the open end of each inflated container.

[0026] The invention further provides an apparatus for forming inflatedcontainers, comprising:

[0027] a. a mechanism that conveys a web of film along a path of travel,the film web comprising a series of pre-formed flexible containers, eachof the pre-formed containers being capable of holding therein a quantityof gas and having an opening for receiving such gas, the conveyingmechanism comprising:

[0028] 1) a support structure for a supply of the film web that allowsthe film web to be withdrawn from the supply,

[0029] 2) a pair of adjacent, counter-rotatable cylinders spaced fromthe film web supply and capable of withdrawing the film web from thefilm web supply by engaging and moving the film web along the travelpath when a portion of the film web passes between the pair of cylindersand the cylinders rotate against the film web, whereby, a moving sectionof the film web is continuously conveyed from the film web supply andthrough the pair of cylinders, the moving section of film web beingunder tension, and

[0030] 3) a device for controlling the tension in the moving section offilm web;

[0031] b. an inflation assembly positioned adjacent the moving sectionof film web and capable of directing a stream of gas into the opening ofeach pre-formed container, thereby forming inflated containers; and

[0032] c. a device for sealing closed the opening of each inflatedcontainer.

[0033] A related method for forming gas-filled cushions comprises thesteps of:

[0034] a. conveying a web of film along a path of travel, the film webcomprising a series of pre-formed flexible containers, each of thepre-formed containers being capable of holding therein a quantity of gasand having an opening for receiving such gas, the conveying stepincluding the steps of:

[0035] 1) withdrawing the film web from a supply of the film web with apair of adjacent, counter-rotatable cylinders spaced from the film websupply, the pair of cylinders engaging and moving the film web alongsaid travel path when a portion of said film web passes between saidpair of cylinders and said cylinders rotate against said film web,whereby, a moving section of said film web is continuously conveyed fromsaid film web supply and through the pair of cylinders, the movingsection of film web being under tension, and

[0036] 2) controlling the tension in the moving section of film web;

[0037] b. directing a stream of gas into the opening of each pre-formedcontainer, thereby forming inflated containers; and

[0038] c. sealing closed the opening of each inflated container.

[0039] An additional aspect of the invention pertains to an apparatusfor forming inflated containers, comprising:

[0040] a. a mechanism that conveys a web of film along a path of travel,the film web comprising a film having a pair of longitudinal side edgesand a longitudinal fold to form a longitudinally-folded film web havingtwo juxtaposed film plies, each of the juxtaposed film plies having aninterior surface disposed in facing relationship with one another andthe side edges being positioned adjacent to one another, the folded filmweb defining

[0041] 1) a closed longitudinal edge formed by the longitudinal fold,

[0042] 2) an open longitudinal edge positioned opposite andsubstantially parallel to the closed longitudinal edge, the openlongitudinal edge formed from the adjacently-positioned longitudinalside edges, and

[0043] 3) one or more pre-formed flexible containers, each of thecontainers being capable of holding therein a quantity of gas and having

[0044] (a) an open edge for receiving such gas, the open edge beingformed by the open longitudinal edge, and

[0045] (b) an opposing closed edge formed by the closed longitudinaledge;

[0046] b. an inflation assembly positioned adjacent the travel path andcapable of directing a stream of gas into the opening of each pre-formedcontainer, wherein one or both of the interior surfaces of thejuxtaposed film plies have a degree of surface abrasion sufficient toallow the stream of gas to flow into the open edge of each container,thereby forming inflated containers; and

[0047] c. a device for sealing closed the opening of each inflatedcontainer.

[0048] These and other aspects and features of the invention may bebetter understood with reference to the following description andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

[0049]FIG. 1 is a side elevational view of an apparatus for forminginflated containers in accordance with the present invention;

[0050]FIG. 2 is a front elevational view of the apparatus shown in FIG.1;

[0051]FIG. 3 is perspective view of a portion of the apparatus shown inFIGS. 1-2, illustrating the inflation and sealing of a container;

[0052]FIG. 4 is a sectional view of the apparatus shown in FIG. 1,illustrating in greater detail the inflation and sealing of a container,with a retaining pin being shown in the foreground;

[0053]FIG. 5 is similar to FIG. 2 and illustrates full (d1) and depleted(d2) supply roll diameters;

[0054]FIG. 6 illustrates the apparatus of FIG. 5 but with the supplyroll in a nearly depleted state; and

[0055]FIG. 7 is a perspective, cross-sectional view of the folded filmshown in FIGS. 1-6.

DETAILED DESCRIPTION OF THE INVENTION

[0056]FIGS. 1 and 2 illustrate an apparatus 10 for forming inflatedcontainers. Apparatus 10 generally includes a conveying mechanism 12, aninflation assembly 14, and a sealing device 16.

[0057] Referring collectively to FIGS. 1-4 and 7, conveying mechanism 12conveys a web of film 18 along a path of travel through apparatus 10 asshown. The “path of travel” (or “travel path”) of film web 18 simplyrefers to the route that the film web traverses while being conveyedthrough the apparatus 10, as indicated by the shape assumed by the filmweb due to the manipulation thereof by the below-described conveyingmechanism 12 and inflation assembly 14 of apparatus 10.

[0058] Film web 18 may, in general, comprise any flexible material thatcan be manipulated by apparatus 10 and enclose a gas as hereindescribed, including various thermoplastic materials, e.g., polyethylenehomopolymer or copolymer, polypropylene homopolymer or copolymer, etc.Non-limiting examples of suitable thermoplastic polymers includepolyethylene homopolymers, such as low density polyethylene (LDPE) andhigh density polyethylene (HDPE), and polyethylene copolymers such as,e.g., ionomers, EVA, EMA, heterogeneous (Zeigler-Natta catalyzed)ethylene/alpha-olefin copolymers, and homogeneous (metallocene,single-cite catalyzed) ethylene/alpha-olefin copolymers.Ethylene/alpha-olefin copolymers are copolymers of ethylene with one ormore comonomers selected from C₃ to C₂₀ alpha-olefins, such as 1-butene,1-pentene, 1-hexene, 1-octene, methyl pentene and the like, in which thepolymer molecules comprise long chains with relatively few side chainbranches, including linear low density polyethylene (LLDPE), linearmedium density polyethylene (LMDPE), very low density polyethylene(VLDPE), and ultra-low density polyethylene (ULDPE). Various othermaterials are also suitable such as, e.g., polypropylene homopolymer orpolypropylene copolymer (e.g., propylene/ethylene copolymer),polyesters, polystyrenes, polyamides, polycarbonates, etc. The film maybe monolayer or multilayer and can be made by any known coextrusionprocess by melting the component polymer(s) and extruding or coextrudingthem through one or more flat or annular dies.

[0059] As shown in greater detail in FIG. 7, film web 18 comprises afilm having a pair of longitudinal side edges, 20 a and 20 b, and alongitudinal fold 22 to form a longitudinally-folded film web having twojuxtaposed film plies, 24 a and 24 b, with side edges 20 a, b beingpositioned adjacent to one another and with respective interior surfaces25 a and 25 b of juxtaposed film plies 24 a, b being disposed in facingrelationship with one another. The folded film web 18 thus defines aclosed longitudinal edge 26, formed by longitudinal fold 22, and an openlongitudinal edge 28. Open longitudinal edge 28 is positioned oppositeand substantially parallel to closed longitudinal edge 26, and is formedfrom adjacently-positioned longitudinal side edges 20 a, b. That is, thefilm is folded longitudinally (i.e., length-wise) such that side edges20 a, b are brought together or at least closer together such that theyare adjacent to one another. Thus, the film may be ‘center-folded’ asshown such that each of film plies 24 a, b have substantially the samedimensions and the longitudinal side edges 20 a, b are substantiallyaligned and thus have the same distance from longitudinal fold 22, i.e.,the longitudinal fold 22 is located approximately in the center of thewidth of the film. Alternatively, side edges 20 a, b may be off-set ifdesired, i.e., where the longitudinal fold 22 is not located in thecenter of the width of the film but is, instead, off-center. As usedherein with reference to film web 18, the term “longitudinal” refers tothe direction of conveyance of film web 18 through apparatus 10 asindicated in the drawings; “longitudinal” also corresponds to thedirection of the length dimension (longest dimension) of film web 18.

[0060] By virtue of being folded in this manner, film web 18 defines atleast one pre-formed, partially completed container that may be filledwith gas, e.g., air, and completed by apparatus 10 to enclose the gas.Preferably, film web 18 includes one or more pre-formed flexiblecontainers 30, e.g., a series of such pre-formed containers, which maybe formed by a series of transverse heat seals 32. Each of the heatseals 32 preferably extends from closed longitudinal edge 26 andtransversely bonds the juxtaposed film plies 24 a, b together such thatfilm web 18 is segregated into a series of pre-formed flexiblecontainers 30 as shown. Preferably, the transverse heat seals 32 eachhave a first end 33 and a second end 35, with the first end 33 locatedat closed longitudinal edge 26 and the second end 35 terminating apredetermined distance from open longitudinal edge 28 as shown.

[0061] Transverse heat seals 32 may be formed ‘in-line’ by apparatus 10or, more preferably, ‘off-line,’ i.e. prior to loading film web 18 ontoapparatus 10.

[0062] Each of the pre-formed containers 30 are capable of holdingtherein a quantity of gas and have an open edge 34 for receiving suchgas, as well as an opposing closed edge 36. Open edge 34 of eachcontainer 30 is formed by open longitudinal edge 28 of film web 18 whileclosed edge 36 is formed by closed longitudinal edge 26. Preferably,each container 30 has a longitudinal length, i.e., the distance betweenthe pair of transverse heat seals 32 defining each container, rangingfrom about 3 to about 10 inches, and more preferably, from about 4 toabout 7 inches. If desired, each of the pre-formed containers 30 mayinclude one or more individual channels in which gas may be held.

[0063] Referring now to FIGS. 1-4, inflation assembly 14 preferablyincludes an air blower 38, a plenum housing 40, and an inflation port42. Air blower 38 generates a stream of air or other gas 44, which isdirected through plenum housing 40 and exits the inflation assembly 14through inflation port 42, preferably at a gas pressure ranging fromabout 0.25 to about 5 inches H₂O over atmospheric pressure (i.e., fromabout 0.01 to about 0.18 psig). The inventors hereof have determinedthat, in order for pre-formed containers 30 to fully and reliablyinflate with gas from inflation assembly 14, closed edge 36 of eachcontainer should be creased, i.e., buckled, as the containers areinflated. This is accomplished in accordance with the present inventionby inflation assembly 14, which, in conjunction with conveying mechanism12, is capable of urging open longitudinal edge 28 of film web 18towards closed longitudinal edge 26 as the film web is conveyed pastinflation port 42. In this manner, at least one crease 46 forms at theclosed edge 36 of each of the pre-formed containers 30, therebysequentially converting each container 30 into a creased, pre-formedcontainer 48 as shown. Stated another way, by urging open longitudinaledge 28 towards closed longitudinal edge 26, closed edge 36 of creasedcontainer 48 has a shorter length than that of open edge 34, with thedifference in lengths being due to creases 46 in closed edge 36. Suchcreasing, or differences in edge length, has been found to greatlyfacilitate the inflation of the containers by air or other gas.Inflation preferably occurs while each container is in a creasedposition as shown at 48, e.g., just after or simultaneous with theformation of the creases 46.

[0064] Inflation port 42 of inflation assembly 14 is positioned adjacentthe travel path of film web 18 such that gas stream 44 may be directedinto the open edge 34 of each creased, pre-formed container 48, therebyinflating each container. Sealing device 16 seals closed the open edge34 of each inflated container, thereby forming completed, i.e., inflatedand sealed, cushions 50.

[0065] In order to urge open longitudinal edge 28 of film web 18 towardsclosed longitudinal edge 26 to form creased, pre-formed containers 48,inflation assembly 14 may include a platform 52, which includes an outersurface 54 located immediately adjacent to open longitudinal edge 28 offilm web 18 as the film web is conveyed along the travel path. Inflationport 42 is disposed in outer surface 54, and is thereby positioned todirect gas stream 44 into creased containers 48 via the open edge 34thereof. As shown, outer surface 54 is preferably positioned at an anglerelative to closed longitudinal edge 36, i.e., relative to the directionof travel of closed longitudinal edge 36 as film web 18 is conveyedthrough apparatus 10. Such angle of outer surface 54 serves to directopen longitudinal edge 28 towards the closed longitudinal edge 26 asfilm web 18 is conveyed past the outer surface.

[0066] As discussed in further detail below, film web 18 is preferablyprovided in the form of a supply roll 56, which may be wound on spool 58and mounted on shaft 60, which, in turn, is affixed to plenum housing40. The supply roll 56 is preferably mounted such that film web 18 maybe advanced, i.e., unwound, from the roll in a substantially verticaldirection as shown. Thus, but for platform 52 and angled outer surface54, both the closed and open longitudinal edges 26, 28 would extend fromsupply roll 56 in substantially parallel, vertical directions. Relativeto the vertical or other direction in which longitudinal edges 26, 28would otherwise extend but for platform 52 and angled outer surface 54,outer surface 54 may have any desired angle ranging, e.g., between 0°and 90°, with 0° being vertical (or parallel to the direction in whichlongitudinal edges 26, 28 would otherwise extend from supply roll 56)and 90° being horizontal (or perpendicular to the direction in whichlongitudinal edges 26, 28 would otherwise extend from supply roll 56).Preferably, the angle of outer surface 54 ranges between about 1° andabout 20° and, more preferably, between about 1° and 10°. For example,outer surface 54 may be angled at 6° from vertical when film web 18 isconveyed in a substantially vertical direction from supply roll 56.

[0067] In some embodiments, contact between the open longitudinal edge28 and angled outer surface 54 may be sufficient to urge the openlongitudinal edge towards closed longitudinal edge 26 to an extentnecessary to effect or facilitate inflation. More preferably, conveyingmechanism 12 includes a pair of adjacent, counter-rotatable cylinders 62and 64 that are mounted on the angled, outer surface 54 of platform 52.Cylinders 62, 64 are capable of engaging and moving film web 18 alongits travel path through apparatus 10 when a portion of the film webpasses between the cylinders and the cylinders rotate in the directionindicated in FIG. 2 against the film web. By virtue of being mounted onthe angled outer surface 54, cylinders 62, 64 rotate against film web 18in the same plane as outer surface 54 and, thus, at an angle withrespect to closed longitudinal edge 26, i.e., at least with respect tothe direction in which the closed longitudinal edge would extend but forthe interference/alteration in the movement of film web 18 caused byplatform 52 and angled outer surface 54, e.g., the vertical direction.Further, cylinders 62, 64 engage the portion of film web 18 in thevicinity of the open longitudinal edge 28. In this manner, as thecounter-rotating cylinders 62, 64 drive the film web 18 through theapparatus as shown, they also have the effect of pushing the openlongitudinal edge 28 towards the closed longitudinal edge 26, therebyproducing creases 46 to facilitate the inflation of container 48.

[0068] When cylinders 62, 64 are utilized in combination with inflationassembly 14 in this fashion, open longitudinal edge 28 of film web 18may be in contact with outer surface 54, closely spaced therefrom, or aportion of the open longitudinal edge may be in contact with the outersurface 54 while another portion may be spaced from the outer surface asshown. Preferably, that portion of the open longitudinal edge 28 that isimmediately adjacent the inflation port 42 is spaced from outer surface54, and therefore from the inflation port, by a distance of about 1 inchor less and, more preferably, about 0.5 inch or less.

[0069] If desired, platform 52 and angled, outer surface 54 may beomitted such that inflation port 42 is disposed in plenum housing 40, orextended therefrom via an appropriate duct or channel, andcounter-rotatable cylinders 62, 64 are positioned adjacent the inflationport, wherein the cylinders alone, i.e., without the assistance ofangled, outer surface 54, urge the open longitudinal edge 28 towards theclosed longitudinal edge 26 to form creases 46, e.g., by being mountedon plenum housing 40 such that the cylinders 62, 64 rotate in a planethat is angled with respect to closed longitudinal edge 26 as explainedabove. In such an embodiment, the inflation port 42 is locatedimmediately adjacent to the open longitudinal edge 28 as the film web 18is conveyed along the travel path so that the inflation port can directthe gas stream 44 into the creased, pre-formed containers 48.

[0070] The spacing between second end 35 of transverse heat seals 32 andopen longitudinal edge 28 has been found to help initiate the inflationof the containers 30 (or 48 when creased) by helping to ensure that thejuxtaposed film plies 24 a, b remain separated at open longitudinal edge28, i.e., are not forced together by the force of gas stream 44, whenthe transverse heat seals 32 move past inflation port 42 as film web 18is conveyed through apparatus 10. The optimal distance between thesecond ends 35 of heat seals 32 and open longitudinal edge 28 may bedetermined by one having ordinary skill in the art without undueexperimentation, based on having sufficient distance between ends 35 andedge 28 to provide an ‘skirt’ that remains open as film web 18 isconveyed past inflation port 42, but not so great a distance that filmis wasted (such film between ends 35 and edge 28 do not contribute tothe interior volume of completed cushions 50). Such distance may range,for example, from about 0.2 to about 0.6 inch, more preferably fromabout 0.25 to about 0.5 inch.

[0071] Separation of juxtaposed film plies 24 a, b during inflation maybe further ensured by mechanically abrading one or both interiorsurfaces 25 a, b of the juxtaposed film plies 24 a, b. That is, one orboth of the interior surfaces 25 a and/or 25 b preferably has a degreeof surface abrasion sufficient to allow gas stream 44 from inflationport 42 to flow into the open edge 34 of each container 30 (or 48 whencreased). Such surface abrasion is preferably provided in the form of atleast one strip 27 on interior surfaces 25 a and/or 25 b adjacent tolongitudinal side edges 20 a and/or 20 b (shown in FIG. 7 only oninterior surface 25 b for clarity). Surface abrasion on interiorsurfaces 25 a and/or 25 b has been found to prevent film plies 24 a, bfrom “blocking,” i.e., undesirably adhering together, during inflation,which could otherwise prevent inflation of the containers, particularlyif film plies 24 a, b adhered together at open longitudinal edge 28(9.e., adjacent longitudinal side edges 20 a, b) such that gas pressurefrom inflation port 42 could not force the film plies open sufficientlyto allow gas stream 44 to flow into the open edge 34 of each container.Preferably, interior surfaces 25 a and/or 25 b are mechanically abradedwith an abrasive surface having a surface roughness ranging from about60 to about 100 grit, e.g., 60-100 grit sandpaper, pressed against thesurfaces 25 a and/or 25 b at a force ranging from about 0.5 to about 5lb_(f). For example, when gas stream 44 exits inflation port 42 at a gaspressure of about 1 inch H₂O over atmospheric pressure (0.036 psig), apair of abraded strips 27 are provided on both interior surfaces 25 a, bby bringing such surfaces into contact at about 1 lb_(f) with anabrasive surface having a surface roughness of about 80 grit.Preferably, abraded strips 27 are applied to interior surfaces 25 aand/or 25 b prior to forming transverse heat seals 32, and such strips27 extend below the second end 35 of each heat seal 32. This ispreferably done ‘off-line’ by first center-folding the film web, thenpassing both folded plies against a pair of planar abrasive surfacesinserted within the film fold to abrade both interior surfaces 25 a, bsimultaneously, then forming transverse heat seals 32.

[0072] When platform 52 and angled, outer surface 54 are employed, it ispreferred that sealing device 16 is mounted on such outer surface 54 asshown. Sealing device 16 is preferably located immediately adjacent andslightly ‘downstream’ of inflation port 42 so that the open edge 34 ofeach creased container 48 is sealed closed immediately after and/orcontemporaneously with the inflation of container 48 by gas stream 44from inflation port 42. Sealing device 16 preferably seals closed theopen edge 34 of each creased container 48 by continuously sealing closedthe entire open longitudinal edge 28.

[0073] A preferred sealing device is disclosed in commonly-assigned,copending patent application Ser. No. 09/760,105 entitled DEVICE FORSEALING TWO PLIES OF FILM TOGETHER, PARTICULARLY FOR ENCLOSING AFOAMABLE COMPOSITION IN A FLEXIBLE CONTAINER (Sperry et al.), filed onJan. 12, 2001 and bearing attorney docket number D-20084-01, thedisclosure of which is hereby incorporated herein by reference. Such asealing device, as perhaps best shown in FIG. 3, includes anelectrically conductive heating element 66 having a first end secured toa first node 68 and a second end secured to a second node 70. Heatingelement 66 is positioned between cylinders 62, 64 such that cylinder 62rotates against the heating element, which is stationary and fixed toouter surface 54 via nodes 68 and 70. Cylinder 62 preferably includes acircumferential groove in which heating element 66 ‘rides’ as cylinder62 rotates against the heating element 66.

[0074] The opening edge 34 of each creased container 48 is sealed closedwhen conveying mechanism 12 brings film web 18 into moving contact withheating element 66 between cylinders 62, 64 and sufficient current iscaused to flow through the heating element that it (i.e., the heatingelement 66) heats to a sealing temperature sufficient to formlongitudinal heat seal 72 between juxtaposed film plies 24 a and 24 b offilm web 18. Longitudinal heat seal 72 seals closed the openlongitudinal edge 28 of film web 18 and also intersects each of thetransverse heat seals 32 as shown, preferably at second ends 35 thereof.In this manner, the open edge 34 of each creased container 48 is sealedclosed, after gas 44 has been directed into such containers by inflationassembly 14, thereby trapping, i.e., enclosing, gas 44 within eachcontainer, resulting in the formation of completed cushions 50.

[0075] When film web 18 is formed from a thermoplastic film, the sealingtemperature necessary to form longitudinal heat-seal 72 is that whichcauses the film plies 24 a, b to weld or fuse together by becomingtemporarily fully or partially molten in the area of contact with theheating element 66. Such temperature, i.e., the “sealing temperature,”may readily be determined by those of ordinary skill in the art withoutundue experimentation for a given application based on, e.g., thecomposition and thickness of the film plies to be sealed, the speed atwhich the film plies move against the heating element, and the pressureat which the film plies and heating element are urged together betweencylinders 62, 64. As an example, when film web 18 comprisespolyethylene-based film ranging in thickness from about 0.001 to about0.003 inch (for a combined, juxtaposed thickness ranging from 0.002 to0.006 inch when the film plies 24 a, b are folded as shown), the sealingtemperature to which heating element 66 is heated preferably ranges fromabout 300 to about 500° F.

[0076] Heating element 66 may be any device capable of heating to apredetermined temperature sufficient to heat-seal film plies 24 a, btogether. Suitable types of devices for heating element 66 include oneor more wires comprising metal and/or other electrically conductivematerials; one or more ribbons comprising metal; circuit-printed plasticribbons, e.g., metal printed on a plastic substrate comprisingpolyethylene terephthalate (PET); and other suitable electricallyconductive devices.

[0077] The drawings illustrate heating element 66 in the form of a wire.When heating element 66 assumes such a form, the wire may have anydesired cross-sectional shape, including round, square, oval,rectangular, etc.

[0078] An alternative sealing device which may be used in the apparatus10 in accordance with the present invention employs a heating elementthat is completely wrapped about the outer circumference of a cylinder,as disclosed in the above-incorporated U.S. Pat. No. 5,376,219. As afurther alternative to employing the sealing device 16 as describedabove, one or both of film plies 24 a, b may include strips of a bondingmaterial located at or adjacent to longitudinal side edges 20 a and/or20 b of film web 18. Such a bonding material, e.g., an adhesive orcohesive material, forms a longitudinal seal similar to seal 72 when thefilm plies 24 a, b are pressed together between cylinders 62, 64.Further details concerning this means for sealing two film pliestogether are described in copending U.S. Ser. No. 09/591,830, filed Jun.12, 2000 and entitled METHOD FOR ENCLOSING A FOAMABLE COMPOSITION IN AFLEXIBLE BAG (Oberle et al.), the disclosure of which is herebyincorporated herein by reference.

[0079] The completed cushions 50 may be collected in a basket or othersuitable container, schematically represented at 74 in FIG. 1, untilneeded for use. Preferably, each of the cushions 30 are manuallydetachable from film web 18, and therefore each completed cushion 50 ismanually detachable from adjacent completed cushions 50, along one ormore transverse lines of weakness 76. As shown, transverse lines ofweakness 76 preferably extend from closed longitudinal edge 26 to openlongitudinal edge 28, and are positioned between transverse heat seals32 from adjacent pre-formed containers.

[0080] The inventors hereof have determined that a further importantcomponent of proper cushion inflation is control of the tension in thatportion of film web 18 that is conveyed past inflation port 42, i.e.,the section of film web 18 that is in motion between supply roll 56 andcylinders 62, 64. If the tension in such section of film web 18 is toohigh, the pre-formed containers 30 cannot fully inflate or, in extremecases, cannot be inflated to any significant extent. On the other hand,if the tension in that section of film web 18 is too low, the film webdoes not track properly through apparatus 10, e.g., the web travels outof the ‘nip’ between cylinders 62, 64 or the film plies 24 a, b do notremain consistently or continually open at open longitudinal edge 28,thereby preventing a complete or uniform degree of inflation ofcontainers 30.

[0081] Conveying mechanism 12 preferably includes a support structurefor a supply of film web 18 that allows the film web to be withdrawnfrom such supply. As discussed briefly above, a preferred film websupply is supply roll 56, wherein a roll of film web 18 is wrapped aboutspool 58, and a preferred support structure for the supply roll is shaft60 mounted to plenum housing 40. Supply roll 56 rotates on or with shaft60 when film web 18 is withdrawn from the supply roll. That is, shaft 60may remain stationary while supply roll 56 rotates thereon or, as analternative, spool 58 may be non-rotatably secured to shaft 60, withshaft 60 being rotatably mounted to plenum housing 40.

[0082] Adjacent, counter-rotatable cylinders 62, 64 are spaced fromsupply roll 56 and capable of withdrawing film web 18 from the supplyroll by engaging and moving the film web when a portion of the film webpasses between the cylinders and the cylinders rotate against the filmweb. This withdrawal of film web 18 by cylinders 62, 64 exerts atensioning force on the film web, which pulls the film web from thesupply roll 56. As a result, a moving section 78 of film web 18 iscontinuously conveyed from supply roll 56 and through the cylinders 62,64 when the cylinders withdraw the film web from supply roll 56. Asperhaps most clearly delineated in FIG. 5, moving section 78 is thatportion of film web 18 that has been withdrawn from supply roll 56 andis in motion towards adjacent cylinders 62, 64 at any given time whilefilm web 18 is being conveyed along its travel path through apparatus10. Such moving section 78 of film web 18 is under tension as a resultof being pulled from supply roll 56 by cylinders 62, 64. The inventorshereof have determined, however, that such tension has a propensity tovary as the amount of film web 18 contained on supply roll 56 depletes.

[0083] Specifically, with reference to FIG. 5, when the supply roll 56is ‘full,’ i.e., contains the maximum amount of film web 18 that will beaccommodated by the roll, the diameter of film web 18 contained on thesupply roll is “d1” (film web 18 is shown in phantom in FIGS. 5 and 6for clarity). Just prior to the depletion of the supply of film web 18on supply roll 56, the diameter of the roll is “d2,” the minimumdiameter of the supply roll. When the diameter of the supply roll is atthe maximum diameter d1, the force required to withdraw the film webfrom the roll is at a minimum because the distance between the outercircumference 80 of supply roll 56 and shaft 60 is at a maximum, andtherefore maximum leverage exists between the outer circumference 80 andshaft 60. For the same reason, the force required to withdraw the filmweb 18 from supply roll 56 is at a maximum when the supply of film webhas been nearly depleted such that the diameter of the roll is at d2.Thus, the tension in moving section 78 of film web 18 is at a minimumwhen the supply roll is full, i.e., has diameter d1, and such tension inmoving section 78 gradually increases as the film web supply isdepleted, i.e., as the diameter of the supply roll decreases towards d2.

[0084] This change in the tension in moving section 78 makes itdifficult to properly and reproducibly inflate each of the pre-formedcontainers 30 that are defined in supply roll 56. If the tension inmoving section 78 is optimized to achieve proper inflation of thecontainers 30 when supply roll 56 is full (diameter d1), such tensionwould gradually increase as the supply roll 56 depletes to a point wherethe tension would be too great to allow the containers to be inflated.On the other hand, if the tension were optimized based on the forcerequired to withdraw film web 18 when the supply roll was near depletion(diameter d2), the tension in moving section 78 would be too low whenthe supply roll 56 is full or nearly so such that film web 18 would nottrack properly to allow inflation of containers 30 while being conveyedthrough apparatus 10.

[0085] In accordance with the practice of the present invention,therefore, a device 82 is preferably provided for controlling thetension in the moving section 78 of film web 18 between supply roll 56and cylinders 62, 64. More specifically, tension-control device 82reduces the variation in tension in moving section 78 such that thetension in section 78 remains substantially constant from the initialwithdrawal of film web 18 from a full supply roll 56 when it is full(diameter d1), and through the depletion of such supply roll (diameterd2).

[0086] Tension-control device 82 preferably includes a frictional member84 that is frictionally engageable with supply roll 56, i.e., capable ofapplying to supply roll 56 a frictional force that opposes the rotationof the supply roll. Frictional member 84 may take the form of a band,wire, arm that is biased against supply roll 56, or any other elementthat acts as a brake against the rotation of supply roll 56. Thefrictional member may be frictionally engageable with supply roll 56either directly or indirectly, i.e., it may contact the supply rolldirectly or may contact an auxiliary component that is associated withthe supply roll and rotationally coupled thereto. As perhaps bestillustrated in FIG. 4, frictional member 84 is preferably in the form ofa stationary band, e.g., constructed from stainless steel and having awidth of about 0.5 inch, that is in frictional contact with frictionwheel 86. Friction wheel 86 is, in turn, rotationally coupled to supplyroll 56 such that supply roll 56 cannot rotate on shaft 60 without alsocausing friction wheel 86 to rotate. Friction wheel preferably has adiameter ranging from about 2 to about 8 inches, more preferably fromabout 3 to about 5 inches, and may be constructed of polycarbonate.Frictional member 84 thus acts as a brake or drag against the rotationof friction wheel 86, and therefore also against the rotation of supplyroll 56, particularly when a weighted object is suspended from thefrictional member or the frictional member 84 is otherwise biased awayfrom friction wheel 86, e.g., with a spring, in order to increase thefrictional force applied against the wheel 86 by frictional member 84.

[0087] Preferably, the tension-control device 82 also includes somemeans for varying the frictional force applied to supply roll 56 by thefrictional member 84 in response to changes in the tension in movingsection 78 of film web 18. Such means may include a movable base 88 uponwhich cylinder pair 62, 64 are mounted. The movable base 88 is movabletowards and away from supply roll 56, and also attachable to frictionmember 84, e.g., via hook 90, such that movement of the movable base 88towards supply roll 56 causes a decrease in the frictional force appliedto the supply roll by frictional member 84. That is, the movable base 88with cylinders 62, 64 mounted thereon has a weight ranging from, e.g.,about 1-10 pounds, and is suspended from friction member 84 via hook 90.This weight thus causes frictional member 84 to exert a frictional forceagainst the rotation of friction wheel 86 and, coupled thereto, supplyroll 56. When the base 88 is caused to move towards supply roll 56, theamount of frictional force against the rotation of the supply rolldecreases.

[0088] When the full weight of movable base 88 is suspended fromfrictional member 84, as shown in FIG. 5, the resultant frictional forceagainst the rotation of supply roll 56 will be at a maximum. Thisadditional frictional force increases the force required to withdrawfilm web 18 from supply roll 56 (i.e., in addition to the force normallyrequired to withdraw the film web notwithstanding the effects offrictional member 84), thereby increasing the tension in moving section78 to the maximum extent. If necessary or desired to increase thetension in moving section 78, additional weight may be added to movablebase 88 or movable base 88 may be biased away from supply roll 56, e.g.,via opposing spring tension.

[0089] As shown in FIG. 6, when movable base 88 moves towards supplyroll 56, the friction-induced increase in tension in moving section 78decreases, as less of the weight of the movable base pulls on frictionalmember 84, thereby allowing the friction member 84 to be more slack andcontact friction wheel 86 with less frictional force in comparison tothe more taught/higher frictional contact state of the friction member84 as shown in FIG. 5.

[0090] Accordingly, when supply roll 56 is full (diameter d1), the forceotherwise required to withdraw film web 18 from the supply roll is at aminimum as explained above. However, when supply roll 56 is full, themovable base 88 is preferably at it lowest point (i.e., farthest awayfrom supply roll 56) such that the maximum amount of frictional force isapplied against the rotation of supply roll 56 and, therefore, thefriction-induced increase in tension in moving section 78 is at amaximum.

[0091] As the supply roll 56 begins to deplete, the diameter decreasesfrom d1 to d2 and the force required to withdraw film web 18 from thesupply roll increases, which would otherwise result in an increase inthe tension in moving section 78 of film web 18. However, such increasein tension does not occur in accordance with the present invention. Asthe tension begins to increase in moving section 78, i.e., when theforce required to withdraw film web 18 from supply roll 56 increases asthe supply of film web 18 and, therefore, the diameter of the supplyroll, decreases, the increase in tension in moving section 78 causescylinders 62, 64 to exert a greater pulling or tensile force on film web18 and this, in turn, causes movable base 88 to move towards supply roll56 as illustrated in FIG. 6, thereby decreasing the frictional forceapplied to the supply roll by frictional member 84 so that the tensionin moving section 78 decreases. Thus, the decrease in tension in movingsection 78 caused by the movement of movable base 88 towards supply roll56 offsets the increase in tension in such section as caused by thedepletion of the supply of film web 18 on supply roll 56. As a result,the tension in moving section 78 remains sufficiently consistent toallow reliable and reproducible inflation of pre-formed containers 30,regardless of whether the diameter of supply roll 56 is at d1, d2, oranywhere in between. In this manner, the tension in moving section 78may be controlled, e.g., to remain within the range of 2 to 4 lb_(f).

[0092] Preferably, movable base 88 is movably mounted to platform 52such that movable base 88 provides outer surface 54 as shown, withcylinders 62, 64 and sealing device 16 being affixed to movable base 88at outer surface 54. Movable base 88 may be mounted to platform 52 witha pair of retaining pins 92, which pass through slots 94 in the movablebase and are attached to platform 52. Slots 94 are shaped to allow themovable base to move both towards and away from supply roll 56.

[0093] Inflation port 42 preferably extends through movable base 88 andis disposed in outer surface 54. Both platform 52 and movable base 88,as well as outer surface 54, are preferably positioned at an angle,relative to closed longitudinal edge 26 of film web 18, in order todirect the open longitudinal edge 28 towards the closed longitudinaledge as film web 18 is conveyed past inflation port 42 by cylinders 62,64, to thereby form creased containers 48 as discussed above. Cylinders62, 64 are preferably mounted on the angled, outer surface 54 adjacentto inflation port 42 as shown.

[0094] Moving section 78 of film web 18 preferably extends across atleast a portion of inflation port 42. This is preferred since thetension in moving section 78 is controlled as discussed above, andtherefore inflation of containers 30, and most preferably creasedcontainers 48, occurs in this section of film web 18.

[0095] Inflation port 42 is preferably shaped such that film web 18,preferably moving section 78 thereof, continuously extends across atleast a portion of the inflation port as the travel path of film webchanges, which occurs as the supply of film web 18 on supply roll 56 isdepleted. For example, as illustrated, inflation port 42 has a wedge orpie shape that is sufficiently wide so that film web 18 extends acrossthe inflation port when supply roll 56 is full, i.e., at diameter d1(FIG. 5), when the supply roll is empty (diameter d2, FIG. 6), and atall diameters in between d1 and d2.

[0096] One or both cylinders 62, 64 are preferably coupled to anelectrical, hydraulic, or pneumatic motor, represented schematically at96 in FIG. 4, having a rotational output to cause the cylinders torotate. For example a single motor, such as an electrical “gear head”motor, may be axially coupled to cylinder 62, which causes cylinder 62to rotate when power (e.g., electricity) is supplied to the motor. Whencylinder 62 is positioned in abutting relationship with cylinder 64 asshown, the rotation of cylinder 62 causes cylinder 64 to rotate.Alternatively, motor 96 could be coupled instead to cylinder 64 or, as afurther alternative, separate drive motors could be coupled to each ofcylinders 62, 64.

[0097] The foregoing description of preferred embodiments of theinvention has been presented for purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise form disclosed, and modifications andvariations are possible in light of the above teachings or may beacquired from practice of the invention.

What is claimed is:
 1. An apparatus for forming inflated containers,comprising: a. a mechanism that conveys a web of film along a path oftravel, said film web comprising a film having a pair of longitudinalside edges and a longitudinal fold to form a longitudinally-folded filmweb having two juxtaposed film plies with said side edges beingpositioned adjacent to one another, said folded film web defining 1) aclosed longitudinal edge formed by said longitudinal fold, 2) an openlongitudinal edge positioned opposite and substantially parallel to saidclosed longitudinal edge, said open longitudinal edge formed from saidadjacently-positioned longitudinal side edges, and 3) one or morepre-formed flexible containers, each of said containers being capable ofholding therein a quantity of gas and having (a) an open edge forreceiving such gas, said open edge being formed by said openlongitudinal edge, and (b) an opposing closed edge formed by said closedlongitudinal edge; b. an inflation assembly positioned adjacent saidtravel path and capable of 1) urging said open longitudinal edge towardssaid closed longitudinal edge such that a crease forms at the closededge of each of said pre-formed containers, thereby forming creased,pre-formed containers, and 2) directing a stream of gas into the openedge of each creased, pre-formed container, thereby forming inflatedcontainers; and c. a device for sealing closed the open edge of eachinflated container.
 2. The apparatus of claim 1, wherein: a. saidinflation assembly includes a platform comprising an inflation port fromwhich said stream of gas exits said inflation assembly and is directedinto said creased, pre-formed containers; b. said platform has an outersurface located immediately adjacent to said open longitudinal edge assaid film web is conveyed along said travel path; c. said inflation portis disposed in said outer surface; and d. said outer surface ispositioned at an angle, relative to said closed longitudinal edge, whichdirects said open longitudinal edge towards said closed longitudinaledge as said film web is conveyed past said inflation assembly.
 3. Theapparatus of claim 2, wherein a. said conveying mechanism includes apair of adjacent, counter-rotatable cylinders capable of engaging andmoving said film web along said travel path when a portion of said filmweb passes between said cylinders and said cylinders rotate against saidfilm web; and b. said pair of cylinders are mounted on said angled,outer surface of said platform.
 4. The apparatus of claim 3, whereinsaid device for sealing closed said open longitudinal edge is mounted onsaid angled, outer surface.
 5. The apparatus of claim 1, wherein saidinflation assembly comprises: a. an inflation port located immediatelyadjacent to said open longitudinal edge as said film web is conveyedalong said travel path so that said inflation port can direct saidstream of gas into said creased, pre-formed containers; and b. a pair ofadjacent, counter-rotatable cylinders capable of engaging therebetweensaid open longitudinal edge of said film web and urging said openlongitudinal edge towards said closed longitudinal edge, said cylinderspositioned adjacent to said inflation port.
 6. The apparatus of claim 1,wherein said conveying mechanism comprises: a. a support structure for asupply of film web that allows said film web to be withdrawn from saidsupply; b. a pair of adjacent, counter-rotatable cylinders spaced fromsaid film web supply and capable of withdrawing said film web from saidfilm web supply by engaging and moving said film web along said travelpath when a portion of said film web passes between said pair ofcylinders and said cylinders rotate against said film web, whereby, amoving section of said film web is continuously conveyed from said filmweb supply and through said pair of cylinders when said cylinders rotateand withdraw said film web from said supply, said moving section of filmweb being under tension; and c. a device for controlling the tension insaid moving section of film web.
 7. The apparatus of claim 6, wherein a.said film web supply comprises a supply roll of said film web wrappedabout a spool and mounted on said support structure, said supply rollrotating on or with said support structure when said film web iswithdrawn from said supply roll; and b. said tension-controlling devicecomprises 1) a frictional member that is capable of applying to saidsupply roll a frictional force that opposes the rotation of said supplyroll, and 2) means for varying the frictional force applied to saidsupply roll by said frictional member in response to changes in thetension in said moving section of film web being conveyed from saidsupply roll and through said pair of cylinders.
 8. The apparatus ofclaim 7, wherein said means for varying the frictional force applied tosaid supply roll comprises a movable base upon which said pair ofcylinders are mounted, said movable base being movable towards saidsupply roll and attachable to said friction member such that movement ofsaid movable base towards said supply roll causes a decrease in thefrictional force applied to said supply roll by said frictional member,whereby, when the tension increases in said moving section of film webbeing conveyed from said supply roll and through said pair of cylinders,said pair of cylinders cause said movable base to move towards saidsupply roll, thereby decreasing the frictional force applied to saidsupply roll by said frictional member so that the tension in said movingsection decreases.
 9. The apparatus of claim 8, wherein: a. saidinflation assembly includes a platform comprising an inflation port fromwhich said stream of gas exits said inflation assembly and is directedinto said creased, pre-formed containers; b. said movable base ismovably mounted to said platform, said movable base having an outersurface located immediately adjacent to said open longitudinal edge assaid film web is conveyed along said travel path; c. said inflation portextends through said movable base and is disposed in said outer surface;and d. said outer surface of said movable base is positioned at anangle, relative to said closed longitudinal edge, which directs saidopen longitudinal edge towards said closed longitudinal edge as saidfilm web is conveyed past said inflation assembly.
 10. The apparatus ofclaim 9, wherein said pair of cylinders are mounted on said angled,outer surface of said movable base adjacent to said inflation port. 11.The apparatus of claim 6, wherein a. said inflation assembly includes aninflation port from which said stream of gas exits said inflationassembly and is directed into said creased, pre-formed containers; andb. said moving section of film web that is conveyed from said supplyroll and through said pair of cylinders extends across at least aportion of said inflation port.
 12. The apparatus of 2, wherein a. saidfilm web supply comprises a supply roll of said film web wrapped about aspool and mounted on said support structure, said supply roll rotatingon or with said support structure when said film web is withdrawn fromsaid supply roll; b. said supply roll has a diameter, said diameterbeing determined by the amount of film web contained in said supply rolland, as said film web is withdrawn from said supply roll, said diameterdecreases such that the travel path of said film web changes; and c.said inflation port is shaped such that said film web continuouslyextends across at least a portion of said inflation port as the travelpath of said film web changes.
 13. The apparatus of claim 1, whereinsaid film web includes a series of transverse heat seals extending fromsaid closed longitudinal edge and bonding said juxtaposed film pliestogether such that said film web is segregated into a series of saidpre-formed flexible containers.
 14. The apparatus of claim 13, whereinsaid transverse heat seals each have a first end and a second end, saidfirst end located at said closed longitudinal edge and said second endterminating a predetermined distance from said open longitudinal edge.15. The apparatus of claim 13, wherein said device for sealing closedsaid open longitudinal edge is adapted to form a longitudinal heat sealthat bonds said juxtaposed film plies together and intersects each ofsaid transverse heat seals.
 16. The apparatus of claim 1, wherein saidjuxtaposed plies of said film web each have an interior surface disposedin facing relationship with one another, one or both of said interiorsurfaces having a degree of surface abrasion sufficient to allow saidstream of gas from said inflation assembly to flow into the open edge ofeach container.
 17. The apparatus of claim 1, wherein said pre-formedcontainers are manually detachable from said folded film web along oneor more transverse lines of weakness.
 18. The apparatus of claim 17,wherein said transverse lines of weakness extend from said closedlongitudinal edge to said open longitudinal edge and are positionedbetween transverse heat seals from adjacent pre-formed containers.
 19. Amethod for forming gas-filled cushions, comprising: a. conveying a webof film along a path of travel, said film web comprising a film having apair of longitudinal side edges and a longitudinal fold to form alongitudinally-folded film web having two juxtaposed film plies withsaid side edges being positioned adjacent to one another, said foldedfilm web defining 1) a closed longitudinal edge formed by saidlongitudinal fold, 2) an open longitudinal edge positioned opposite andsubstantially parallel to said closed longitudinal edge, said openlongitudinal edge formed from said adjacently-positioned longitudinalside edges, and 3) one or more pre-formed flexible containers, each ofsaid containers being capable of holding therein a quantity of gas andhaving (a) an open edge for receiving such gas, said open edge beingformed by said open longitudinal edge, and (b) an opposing closed edgeformed by said closed longitudinal edge; b. urging said openlongitudinal edge towards said closed longitudinal edge such that acrease forms at the closed edge of each of said pre-formed containers,thereby forming creased, pre-formed containers; c. directing a stream ofgas into the open edge of each creased, pre-formed container, therebyforming inflated containers; and d. sealing closed the open end of eachinflated container.
 20. An apparatus for forming inflated containers,comprising: a. a mechanism that conveys a web of film along a path oftravel, said film web comprising a series of pre-formed flexiblecontainers, each of said pre-formed containers being capable of holdingtherein a quantity of gas and having an opening for receiving such gas,said conveying mechanism comprising: 1) a support structure for a supplyof said film web that allows said film web to be withdrawn from saidsupply, 2) a pair of adjacent, counter-rotatable cylinders spaced fromsaid film web supply and capable of withdrawing said film web from saidfilm web supply by engaging and moving said film web along said travelpath when a portion of said film web passes between said pair ofcylinders and said cylinders rotate against said film web, whereby, amoving section of said film web is continuously conveyed from said filmweb supply and through said pair of cylinders, said moving section offilm web being under tension, and 3) a device for controlling thetension in said moving section of film web; b. an inflation assemblypositioned adjacent said moving section of film web and capable ofdirecting a stream of gas into the opening of each pre-formed container,thereby forming inflated containers; and c. a device for sealing closedthe opening of each inflated container.
 21. The apparatus of claim 20,wherein: a. said film web supply comprises a supply roll of said filmweb wrapped about a spool and mounted on said support structure, saidsupply roll rotating on or with said support structure when said filmweb is withdrawn from said supply roll; and b. said tension-controllingdevice comprises 1) a frictional member that is capable of applying tosaid supply roll a frictional force that opposes the rotation of saidsupply roll, and 2) means for varying the frictional force applied tosaid supply roll by said frictional member in response to changes in thetension in said moving section of film web being conveyed from saidsupply roll and through said pair of cylinders.
 22. The apparatus ofclaim 21, wherein said means for varying the frictional force applied tosaid supply roll comprises a movable base upon which said pair ofcylinders are mounted, said movable base being movable towards saidsupply roll and attachable to said friction member such that movement ofsaid movable base towards said supply roll causes a decrease in thefrictional force applied to said supply roll by said frictional member,whereby, when the tension increases in said moving section of film webbeing conveyed from said supply roll and through said pair of cylinders,said pair of cylinders cause said movable base to move towards saidsupply roll, thereby decreasing the frictional force applied to saidsupply roll by said frictional member so that the tension in said movingsection decreases.
 23. The apparatus of claim 22, wherein: a. said filmweb comprises a film having a pair of longitudinal side edges and alongitudinal fold to form a longitudinally-folded film web having twojuxtaposed film plies with said side edges being positioned adjacent toone another, said folded film web defining 1) a closed longitudinal edgeformed by said longitudinal fold, 2) an open longitudinal edgepositioned opposite and substantially parallel to said closedlongitudinal edge, said open longitudinal edge formed from saidadjacently-positioned longitudinal side edges, and 3) each of saidpre-formed flexible containers include (a) an open edge formed by saidopen longitudinal edge, said open edge providing said opening forreceiving a gas, and (b) an opposing closed edge formed by said closedlongitudinal edge; and b. said inflation assembly is capable of urgingsaid open longitudinal edge towards said closed longitudinal edge suchthat a crease forms at the closed edge of each of said pre-formedcontainers, thereby forming creased, pre-formed containers, into whichsaid stream of gas is directed via said openings.
 24. The apparatus ofclaim 23, wherein: a. said inflation assembly includes a platformcomprising an inflation port from which said stream of gas exits saidinflation assembly and is directed into said creased, pre-formedcontainers; b. said movable base is movably mounted to said platform,said movable base having an outer surface located immediately adjacentto said open longitudinal edge as said film web is conveyed along saidtravel path; c. said inflation port extends through said movable baseand is disposed in said outer surface; and d. said outer surface of saidmovable base is positioned at an angle, relative to said closedlongitudinal edge, which directs said open longitudinal edge towardssaid closed longitudinal edge as said film web is conveyed past saidinflation assembly.
 25. The apparatus of claim 24, wherein said pair ofcylinders are mounted on said angled, outer surface of said movable baseadjacent to said inflation port.
 26. The apparatus of claim 23, whereina. said inflation assembly comprises an inflation port disposed in saidmovable base and located immediately adjacent to said open longitudinaledge as said film web is conveyed along said travel path so that saidinflation port can direct said stream of gas into said creased,pre-formed containers; and b. said pair of adjacent, counter-rotatablecylinders are adapted to engage therebetween said open longitudinal edgeand urge said open longitudinal edge towards said closed longitudinaledge, said cylinders positioned adjacent to said inflation port.
 27. Theapparatus of claim 22, wherein said device for sealing closed theopening of each inflated container is mounted on said movable base. 28.The apparatus of claim 20, wherein a. said inflation assembly includesan inflation port from which said stream of gas exits said inflationassembly and is directed into said creased, pre-formed containers; andb. said moving section of film web that is conveyed from said supplyroll and through said pair of cylinders extends across at least aportion of said inflation port.
 29. The apparatus of 21, wherein a. saidfilm web supply roll has a diameter, said diameter being determined bythe amount of film web contained in said supply roll and, as said filmweb is withdrawn from said supply roll, said diameter decreases suchthat the travel path of said film web changes; and b. said inflationport is shaped such that said film web continuously extends across atleast a portion of said inflation port as the travel path of said filmweb changes.
 30. The apparatus of claim 23, wherein said film webincludes a series of transverse heat seals extending from said closedlongitudinal edge and bonding said juxtaposed film plies together suchthat said film web is segregated into said series of pre-formed flexiblecontainers.
 31. The apparatus of claim 30, wherein said transverse heatseals each have a first end and a second end, said first end located atsaid closed longitudinal edge and said second end terminating apredetermined distance from said open longitudinal edge.
 32. Theapparatus of claim 30, wherein said device for sealing closed said openlongitudinal edge is adapted to form a longitudinal heat seal that bondssaid juxtaposed film plies together and intersects each of saidtransverse heat seals.
 33. The apparatus of claim 20, wherein saidpre-formed containers are manually detachable from said folded film webalong one or more transverse lines of weakness.
 34. The apparatus ofclaim 33, wherein said transverse lines of weakness extend from saidclosed longitudinal edge to said open longitudinal edge and arepositioned between transverse heat seals from adjacent pre-formedcontainers.
 35. The apparatus of claim 23, wherein said juxtaposed pliesof said film web each have an interior surface disposed in facingrelationship with one another, one or both of said interior surfaceshaving a degree of surface abrasion sufficient to allow said stream ofgas from said inflation assembly to flow into the open edge of eachcontainer.
 36. A method for forming gas-filled cushions, comprising: a.conveying a web of film along a path of travel, said film web comprisinga series of pre-formed flexible containers, each of said pre-formedcontainers being capable of holding therein a quantity of gas and havingan opening for receiving such gas, said conveying step including thesteps of: 1) withdrawing said film web from a supply of said film webwith a pair of adjacent, counter-rotatable cylinders spaced from saidfilm web supply, said pair of cylinders engaging and moving said filmweb along said travel path when a portion of said film web passesbetween said pair of cylinders and said cylinders rotate against saidfilm web, whereby, a moving section of said film web is continuouslyconveyed from said film web supply and through said pair of cylinders,said moving section of film web being under tension, and 2) controllingthe tension in said moving section of film web; b. directing a stream ofgas into the opening of each pre-formed container, thereby forminginflated containers; and c. sealing closed the opening of each inflatedcontainer.
 37. An apparatus for forming inflated containers, comprising:a. a mechanism that conveys a web of film along a path of travel, saidfilm web comprising a film having a pair of longitudinal side edges anda longitudinal fold to form a longitudinally-folded film web having twojuxtaposed film plies, each of said juxtaposed film plies having aninterior surface disposed in facing relationship with one another andsaid side edges being positioned adjacent to one another, said foldedfilm web defining 1) a closed longitudinal edge formed by saidlongitudinal fold, 2) an open longitudinal edge positioned opposite andsubstantially parallel to said closed longitudinal edge, said openlongitudinal edge formed from said adjacently-positioned longitudinalside edges, and 3) one or more pre-formed flexible containers, each ofsaid containers being capable of holding therein a quantity of gas andhaving (a) an open edge for receiving such gas, said open edge beingformed by said open longitudinal edge, and (b) an opposing closed edgeformed by said closed longitudinal edge; b. an inflation assemblypositioned adjacent said travel path and capable of directing a streamof gas into the opening of each pre-formed container, wherein one orboth of said interior surfaces of said juxtaposed film plies have adegree of surface abrasion sufficient to allow said stream of gas toflow into the open edge of each container, thereby forming inflatedcontainers; and c. a device for sealing closed the opening of eachinflated container.